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Thursday, November 02, 2006

A variation on my "cruiser killer" fast battlecruiser

This is a moderately fast "cruiser killer" fast battlecruiser. "Cruiser killer" is what Frank Fox calls ships like the American Alaska class ships. He likes the concept very much. Five years ago, I had done a series of designs of fast battlecruisers and armoured cruisers. This is a fresh attempt at such a ship, although with normal weight machinery. That limits the speed to 33 knots. The armour basis is 12in with a 4in deck. The armament is 9-14in BLR, 20-5in QF, 6-4.7in AA, and 16-2pdr AA guns. There are no torpedo tubes. Frank Fox cautions against torpedo tubes, except on destroyers. He points to the Japanese heavy cruiser lost at Midway from exploding torpedoes hit by bombs. This is the Springsharp report:
GB/CB/1923, Great Britain Battlecruiser laid down 1923

Displacement:
 40,354 t light; 41,954 t standard; 44,300 t normal; 46,177 t full load

Dimensions: Length overall / water x beam x draught
 869.31 ft / 867.00 ft x 104.00 ft x 29.00 ft (normal load)
 264.96 m / 264.26 m x 31.70 m  x 8.84 m

Armament:
      9 - 14.00" / 356 mm guns (3x3 guns), 1,372.00lbs / 622.33kg shells, 1923 Model
   Breech loading guns in turrets (on barbettes)
   on centreline ends, majority forward, 1 raised mount - superfiring
      20 - 5.00" / 127 mm guns (10x2 guns), 62.50lbs / 28.35kg shells, 1923 Model
   Quick firing guns in deck mounts with hoists
   on centreline ends, evenly spread, 6 raised mounts - superfiring
      6 - 4.70" / 119 mm guns in single mounts, 51.91lbs / 23.55kg shells, 1923 Model
   Anti-aircraft guns in deck mounts with hoists
   on centreline, all amidships
      16 - 1.57" / 40.0 mm guns (4x4 guns), 2.00lbs / 0.91kg shells, 1923 Model
   Anti-aircraft guns in deck mounts 
   on side, evenly spread, 2 raised mounts
 Weight of broadside 13,941 lbs / 6,324 kg
 Shells per gun, main battery: 90

Armour:
   - Belts:  Width (max) Length (avg)  Height (avg)
 Main: 12.0" / 305 mm 570.00 ft / 173.74 m 8.00 ft / 2.44 m
 Ends: Unarmoured
 Upper: 8.00" / 203 mm 570.00 ft / 173.74 m 8.00 ft / 2.44 m
   Main Belt covers 101 % of normal length
   Main belt does not fully cover magazines and engineering spaces

   - Torpedo Bulkhead:
  2.00" / 51 mm 570.00 ft / 173.74 m 29.00 ft / 8.84 m

   - Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
 Main: 12.0" / 305 mm 8.00" / 203 mm  12.0" / 305 mm
 2nd: 5.00" / 127 mm 5.00" / 127 mm  5.00" / 127 mm

   - Armour deck: 4.00" / 102 mm, Conning tower: 12.00" / 305 mm

Machinery:
 Oil fired boilers, steam turbines, 
 Geared drive, 4 shafts, 221,072 shp / 164,919 Kw = 33.00 kts
 Range 6,500nm at 15.00 kts
 Bunker at max displacement = 4,223 tons

Complement:
 1,526 - 1,984

Cost:
 £11.376 million / $45.505 million

Distribution of weights at normal displacement:
 Armament: 1,743 tons, 3.9 %
 Armour: 13,364 tons, 30.2 %
    - Belts: 3,870 tons, 8.7 %
    - Torpedo bulkhead: 1,223 tons, 2.8 %
    - Armament: 3,099 tons, 7.0 %
    - Armour Deck: 4,848 tons, 10.9 %
    - Conning Tower: 324 tons, 0.7 %
 Machinery: 7,389 tons, 16.7 %
 Hull, fittings & equipment: 17,858 tons, 40.3 %
 Fuel, ammunition & stores: 3,946 tons, 8.9 %
 Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
 Survivability (Non-critical penetrating hits needed to sink ship):
   59,353 lbs / 26,922 Kg = 43.3 x 14.0 " / 356 mm shells or 7.7 torpedoes
 Stability (Unstable if below 1.00): 1.15
 Metacentric height 6.9 ft / 2.1 m
 Roll period: 16.6 seconds
 Steadiness - As gun platform (Average = 50 %): 55 %
   - Recoil effect (Restricted arc if above 1.00): 0.57
 Seaboat quality  (Average = 1.00): 1.10

Hull form characteristics:
 Hull has low forecastle
 Block coefficient: 0.593
 Length to Beam Ratio: 8.34 : 1
 'Natural speed' for length: 29.44 kts
 Power going to wave formation at top speed: 53 %
 Trim (Max stability = 0, Max steadiness = 100): 50
 Bow angle (Positive = bow angles forward): 4.00 degrees
 Stern overhang: 0.00 ft / 0.00 m
 Freeboard (% = measuring location as a percentage of overall length):
    - Stem:  33.00 ft / 10.06 m
    - Forecastle (20 %): 25.00 ft / 7.62 m (26.00 ft / 7.92 m aft of break)
    - Mid (50 %):  26.00 ft / 7.92 m
    - Quarterdeck (15 %): 26.00 ft / 7.92 m
    - Stern:  26.00 ft / 7.92 m
    - Average freeboard: 26.44 ft / 8.06 m

Ship space, strength and comments:
 Space - Hull below water (magazines/engines, low = better): 103.8 %
  - Above water (accommodation/working, high = better): 212.6 %
 Waterplane Area: 65,514 Square feet or 6,086 Square metres
 Displacement factor (Displacement / loading): 105 %
 Structure weight / hull surface area: 193 lbs/sq ft or 941 Kg/sq metre
 Hull strength (Relative):
  - Cross-sectional: 0.99
  - Longitudinal: 1.10
  - Overall: 1.00
 Hull space for machinery, storage, compartmentation is adequate
 Room for accommodation and workspaces is excellent

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